Re: PVHVM VCPU hotplug mechanism via ACPI hotplug doesn't work in Xen 4.[1, 2, 3]

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, May 07, 2013 at 12:35:42PM +0100, Stefano Stabellini wrote:
> On Mon, 6 May 2013, Konrad Rzeszutek Wilk wrote:
> > Which is probably the case b/c the Linux side implementation for
> > such simple operation as :
> > 
> > echo 0 > /sys/devices/system/cpu/cpu1/online
> > echo 1 > /sys/devices/system/cpu/cpu1/online
> > 
> > would have blown up so nobody tested it?
> > 
> > Now that is fixed (v3.10 + http://lists.xen.org/archives/html/xen-devel/2013-05/msg00503.html)
> > I tried to do 'xm vcpu-set latest X' for a PVHVM guest.
> > 
> > The first iteration was using this simple guest config:
> > builder='hvm'
> > disk = [ 'file:/mnt/lab/latest/root_image.iso,hdc:cdrom,r']
> > memory = 2048
> > boot="d"
> > maxvcpus=4
> > vcpus=4
> 
> I think that you might have to set maxvcpus=4 and vcpus=2 if you want to
> be able to hotplug a couple of more vcpus (the last two in this case).

Did that too. It did not work.

Right now I am just trying to de-plug the VCPUs to see if that works. Figured
that tearing down is easier than adding things in.